The present embodiments relate to a magnetic resonance tomography (MRT) local coil for an MRT system.
Magnetic resonance tomography devices for examining objects or patients using magnetic resonance tomography (MRT, MRI, MR) are known, for example, from DE10314215B4.
In MR tomography, images having a high signal-to-noise ratio (SNR) may be acquired by local coil arrangements (e.g., loops, local coils). The local coil arrangements are antenna systems that are mounted in immediate proximity to (e.g., on (anterior) or under (posterior)) the patient. In the course of an MR measurement, the excited nuclei induce a voltage in the individual antennas of the local coil. The induced voltage is amplified by a low-noise preamplifier (e.g., LNA, preamp) and forwarded by a wired connection to the receive electronics. High-field systems (e.g., 1.5 T to 12 T and more) are employed, even in the case of high-resolution images, in order to improve the signal-to-noise ratio. If more individual antennas may be connected to an MR receiving system than there are receivers present, a switching array (e.g., an RCCS) may be installed between receive antennas and receivers. The switching array routes the currently active receive channels (e.g., the receive channels currently lying in the field of view of the magnet) to the receivers present. This enables more coil elements to be connected than there are receivers available, since in the case of whole-body coverage, only the coils that are currently located in the field of view (FoV) or in the homogeneity volume of the magnet of the MRT system may be read out.
The term “coil” (e.g., local coil) is used to refer to an antenna system that may include one antenna element (e.g., a coil element) or of a plurality of antenna elements (e.g., an array coil). Individual antenna elements may be implemented as loop antennas (e.g., loops) or as butterfly or saddle coils. A coil includes, for example, coil elements, one or more preamplifiers, further electronics (e.g., standing wave traps), cabling, a housing, and may include a cable with a plug-type connector, by which the coil is connected to the MRT system. The receiver (RX) mounted on the system side filters and digitizes the signal received by the local coil and passes the data to the digital signal processing device that may derive an image or a spectrum from the measurement. The digital signal processing device makes the image or the spectrum available to the user for diagnostic purposes.
Depending on the number of antenna elements, a local coil includes a different number of electronics modules. Forces in the MR system may act on the electronics modules, potentially causing the electronics modules (e.g., printed circuit boards (PCBs)) to be shaken loose if the PCBs are improperly anchored. For this reason, PCBs are adequately secured in local coils.
An arrangement of the electronics for an antenna element may include an electronics module (e.g., a mainboard), to which the antenna element is soldered and which may be populated on an element-specific basis.
Due to the soldered connections of the antenna and the frequently employed screwed anchorage to the coil housing, the mainboard is not replaceable without effort. Other PCBs (e.g., preamplifiers) may be plugged onto the mainboard. The pluggable components are the same for all the antenna elements and are to be pulled and inserted in order to balance the antenna element. Due to electrical function of the pluggable components, the pluggable components may be more susceptible to faults than the mainboard and consequently may need to be replaced more frequently. The pluggable components are connected electrically and mechanically (e.g., insertion force of the contacts) to the mainboard by way of plug-in contacts (e.g., female and male multipoint connectors). Because of the weight of the pluggable components and the installation position in the respective local coil, the pluggable components may work loose during operation due to the effect of forces introduced by the MR system. In other words, the insertion force of the connector parts may be insufficient as a mechanical fastening, and an additional securing device may be installed.
FIGS. 1 and 2 show a prior art solution.
A mainboard 1 is secured to the coil housing by a screwed connection.
A preamplifier 2 (e.g., an inserted component) is plugged onto the mainboard 1. A retaining clip 3 (also referred to hereinbelow as a bracket or retaining bracket) is snapped into place in the mainboard 1 and secures the inserted component 2 using snap-fit hooks 4. The plug-in parts 5 used possess an insertion depth of at least 5 mm.